Perceived listening ability and hearing loss: Systematic review and qualitative meta-synthesis

Background Hearing loss (HL) can affect communication in complex ways. Understanding how adults with HL reflect on and conceptualise the way they listen (metacognition) is required if interventions, and the outcome measures used to evaluate them, are to address barriers to functional communication arising from HL. Objectives This study describes how adults with HL experience and report the processes, behaviours, and components of listening, as presented in published studies. Design Systematic review and meta-synthesis of qualitative studies. Methods Systematic searches identified English-language, peer-reviewed journal articles reporting the results of qualitative or mixed-methods studies of adults’ with HL perceived listening abilities. Medline, PsychInfo, Web of Science, Embase, and Google Scholar were searched from inception to November 2021. Handsearching reference lists of included studies identified additional studies for inclusion. The Critical Appraisal Skills Programme (CASP) qualitative checklist was used to appraise studies’ methodological quality. Data from included studies were analysed using thematic meta-synthesis. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) Confidence in the Evidence from Reviews of QUALitative (CERQual) approach assessed confidence in the review findings. Two reviewers independently completed all screening and quality appraisal. Thematic meta-synthesis and GRADE CERQual assessment was completed by one reviewer and confirmed by a second reviewer. Discrepancies were resolved through discussion. Results Data from 46 studies were included in the review. Thematic meta-synthesis identified six descriptive themes: 1) perceived listening ability; 2) external modifiers; 3) psychosocial impacts of hearing loss; 4) communication partner perspectives; 5) self-efficacy for listening; and 6) cognitive load. GRADE CERQual ratings for descriptive themes ranged from low to moderate confidence. Descriptive themes were related by analytic themes of liminality and reciprocity. Conclusions Adults with HL provide in-depth accounts of components and processes of listening, with studies reporting both cognitive and affective experiences consistent with theoretical models of metacognition. The findings will inform content generation for a hearing-specific patient-reported outcome measure of perceived listening ability in everyday communication.

Introduction to the target construct are perceivable (i.e., within conscious awareness) by members of the target population and suitable for operationalisation (i.e., whether individuals are able to recognise and appraise the concept, retrieve the required information from memory, judge the applicability of the retrieved information, and estimate a response on a pre-specified scale) [9][10][11].
Theoretical models, when used in conjunction with first-hand accounts of the target construct, can support the framing of a PRO's assessment [11]. In the context of perceived listening ability for functional communication, theories of metacognition could play a supportive role in concept elicitation and generation of a conceptual framework and measurement model. Metacognition refers to "the human ability to be conscious of one's mental process" [12][13][14]. Models of meta-cognition, notably Flavell's seminal Model of Cognitive Monitoring, have been extensively applied within education, particularly in relation to second language listening [15]. Flavell's model describes meta-cognition in terms of the actions and interactions of four distinct phenomena: 1) metacognitive knowledge (defined as the segment of an individual's stored world knowledge that "consists primarily of knowledge of beliefs about what factors or variables act and interact in what ways to affect the course and outcome of cognitive enterprises" (p. 907); 2) metacognitive experiences (any conscious cognitive or affective experiences related to a cognitive task); 3) goals/tasks, and 4) actions/strategies [12]. Metacognitive knowledge may be further classified as knowledge relating to persons, tasks, or strategies. In the context of listening (as a cognitive activity), person knowledge could includer an individual's judgements about their listening abilities and stored knowledge about internal and external factors likely to affect listening success. Task knowledge could include knowledge relating to the purpose, demands, and nature of a listening task. Task knowledge enables individuals to appraise the difficulty of a listening activity to support strategy selection and deployment [12,16,17]. Strategy knowledge may be defined as knowledge useful for achieving listening and/or communication goals.
Conceptualising perceived listening ability as a special type of meta-cognition could support the operationalisation of the concept for measurement as a PRO. A meta-cognitive lens could help to identify domains of perceived listening ability within conscious awareness for adults with HL thereby rendering these concepts candidates for measurement. For example, in the field of second language (L2) learning, Vandergrift et al. (2008) used Flavell's model to underpin the development of the Metacognitive Awareness Listening Questionnaire (MALQ), a self-report instrument designed to assess the extent to which language learners are aware of and can regulate the process of L2 listening comprehension [16]. In relation to HL, metacognition has been studied primarily in children within educational settings. Studies have explored metacognitive awareness during classroom instruction and the impact of metacognitive strategy deployment on reading behaviour and comprehension in deaf and hard-of-hearing students [18,19]. With the exception of studies exploring the role of metacognitive beliefs on distress in tinnitus, comparatively few studies have studied the metacognition of listening explicitly in adults with HL [20]. However, a rich qualitative literature is available relating variously to metacognitive concepts such as the influence of person, task and strategy factors on listening performance in the context of the lived experience of HL. This systematic review and qualitative meta-synthesis use this literature to describe first-hand accounts of adults' with HL listening-related knowledge and experience.

Methods
We reported this systematic review and meta-synthesis in line with the PRISMA guidelines and the Joanna Briggs Institute guidance for systematic reviews of qualitative evidence [21].
The protocol was registered on PROSPERO (Registration number: CRD42020213389), the international prospective register of systematic reviews, and published in a peer-reviewed journal [22].

Search strategy
The search strategy was developed in Medline (Ovid) using terms based on the population (i.e., adults with HL), study design, and terms related to listening (including MeSH terms and their synonyms). The full Medline search strategy is in S1 File. We searched Medline (Ovid), PsychInfo (Ovid), Embase (Ovid), Web of Science, and Google Scholar (first 200 records) from inception to 15th November 2021. Database selection, including Google Scholar, was guided by recommendations for optimal yields proposed by Bramer et al [23]. We handsearched the references lists of the included studies.

Eligibility criteria
Eligible studies were English-language, peer-reviewed manuscripts of primary qualitative or mixed-methods studies that reported first-hand accounts from adults (�18 years of age) with HL and/or their communication partners on their experiences of listening for communication in daily life. Quantitative studies, studies involving or reporting on children as participants, editorial, opinions, and letters were excluded. Only the qualitative data from mixed-methods studies were analysed. No restrictions were placed on the date of publication, country of origin, setting, degree and aetiology of HL, or hearing device. We excluded studies reporting solely on the psychosocial aspects of HL but included those studies that discussed psychosocial impacts of HL alongside an exploration of perceived listening ability. Studies reporting on sign language were excluded. The rationale for the study eligibility criteria is described in detail in the study protocol [22].

Study selection
We uploaded the search results to Endnote (version 9.3, Clarivate Analytics). After duplicates were removed, the remaining records were imported to Covidence web-based systematic review software (www.covidence.org) for screening and data extraction. Two reviewers (KN, SH) independently screened all titles and abstracts and full text articles for eligibility. Reasons for exclusion were documented at the full text screening stage. Disagreements were resolved through discussion or by a third author (IB).

Assessment of the methodological quality of the included studies
Two reviewers (SH, KN) used the Critical Appraisal Skills Programme (CASP) checklist for qualitative research to independently assess the methodological quality of the included studies. Differences were resolved through discussion or by involving a third reviewer. Percentage agreement, Cohen's kappa (κ), as a measure of agreement adjusted for chance, and an intraclass correlation coefficient (ICC) was calculated to establish inter-rater agreement and reliability respectively [24,25]. A kappa value of 0.69-0.79 was considered evidence of "moderate" agreement and κ� 0.80 represented "good" agreement. ICC > 0.75 was indicative of good inter-rater reliability [26].
setting, phenomena of interest, methodological approach, and data collection and analysis methods.

Data synthesis
We uploaded the full-text articles to NVivo (Version 1.5) qualitative data analysis software and analysed the results sections (including both narratives and participant quotes) and relevant supplementary material from the included studies. We used the methodology proposed by Thomas and Harden to conduct the thematic meta-synthesis [27]. First, we completed line-byline coding to label concepts presented in the findings which we then compared across the included studies, grouping these initial codes into higher-level descriptive themes. To provide a rich, nuanced description of the descriptive themes, we used axial coding to develop a further coding paradigm to describe a set of characteristics (subcategories) operating within each descriptive theme [28]. The descriptive themes were then interrogated to reflexively construct a hypothesised model of the proposed relationships amongst the themes. One researcher (SH) completed the inductive line-by-line initial coding. Where relevant, multiple codes were assigned to a single data unit. The coding for ten percent of included studies (n = 5) was reviewed for accuracy by a second researcher (KN). The studies were selected randomly for review using a web-based random number generator. Themes were co-constructed through discussion between the authors (KN, SEH). The discussions were supported by coding and analytical memos that documented coding decisions and theme development. Both authors used reflexive memos to document the researcher lenses which informed their engagement with the analytic process. SH is a PRO researcher and qualified speech and language therapist. KN is a qualified audiologist, hearing researcher, and practicing clinician with lived experience of HL.

Assessment of confidence in the synthesis findings
The Grading of Recommendations Assessment, Development and Evaluation-Confidence in Evidence from Reviews of Qualitative research (GRADE-CERQual) approach was used to establish the degree of confidence that can be applied to the individual, descriptive findings [29]. The data supporting each of the six descriptive themes were appraised against the GRA-DE-CERQual criteria for: 1) methodological limitations; 2) relevance; 3) coherence; and 4) adequacy. An overall rating of confidence of "high", "moderate", "low" or "very low" was assigned to each finding (theme), considering each of the four GRADE CERQual components described in Table 1 [30][31][32][33][34]. Table 1. Overview of the four components of the GRADE-CERQual approach for assessing confidence in findings of reviews of qualitative research.

GRADE-CERQual Component Definition
Methodological limitations "The extent to which there are concerns about the design or conduct of the primary studies supporting a review finding." [32] (p.25) Coherence "An assessment of how clear and cogent that fit is between the data from the primary studies and a review finding that synthesises the data." [30] (p.35) Adequacy "The degree of richness and quantity of data supporting a review finding." [33] (p.45) Relevance "The extent to which the body of data from the primary studies supporting a review finding is applicable to the context specified in the review question." [31]  The aggregated CASP checklist results for the contributing studies were used to assess the methodological limitations of the contributing studies per synthesis finding. Synthesis findings were assessed as having "no or very minor concerns" for coherence if there was "good and consistent fit" between the theme and data from the contributing studies [30,35]. Synthesis findings were assessed as having "no or very minor concerns" for adequacy if more than 50% of the contributing studies contributed to a theme and the data from these studies were sufficiently rich [36]. Synthesis findings were assessed as having "no or very minor concerns" for relevancy if most of the papers included in a descriptive theme address the review question overtly (i.e., perceived listening ability), most participants were adults with HL and their communication partners, and findings addressed listening in everyday communication settings. For all GRADE CERQual components, appraisal began with the assumption that there were no concerns regarding the body of data contributing to each finding with the rating downgraded based on appraisal results. The GRADE CERQual approach was not applied to analytic themes due to the interpretative nature of these higher-order themes [37].

Results
The search outcomes are reported in detail in the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) flow chart (Fig 1). In total, 3,214 records were identified for title and abstract screening. Of these, 2,803 were excluded and 137 underwent full-text review. Forty-six studies met the study eligibility criteria and were included in the review.

Study characteristics
Included studies were published in seven high-income countries (Australia, Canada, Ireland, Norway, Sweden, United Kingdom, USA) and one middle-income country (Brazil) between 1967 and 2021, with 30 studies published since 2010. Mean sample size was 26.4 participants (range = 3-207, SD = 33.4). Five studies (10.9%) included communication partners (e.g., spouses, adult children) and/or healthcare practitioners in the study sample. Twenty-four (52.2%) studies explored the lived experience of HL, ten (21.7%) studies examined adults' with HL experiences with audiological rehabilitation and healthcare consultations, two studies (4.3%) explored listening effort and listening-related fatigue, four studies (8.7%) examined hearing device use, three studies (6.5%) explored adults' with HL musical experiences, and three studies (6.5%) reported findings to inform the development of patient-reported outcome measures (PROMs). None of the studies specifically explored perceived listening ability or adults' with HL meta-cognitive awareness of listening. Most studies used interviews (n = 27, 58.7%) as a data collection method. Seven studies (15.2%) used focus groups, three studies (6.5%) used survey techniques and nine studies (19.6%) used a multi-methods approach. Data analysis methods used most often were thematic analysis (n = 15, 32.6%), content analysis (n = 6, 13.0%), and grounded theory (n = 13, 28.3%). Characteristics of the included studies are summarised in S1 Table.

Methodological quality of studies
None of the included studies were excluded following appraisal of their methodological quality. Table 2 presents a summary of the quality appraisal using the CASP assessment tool [38]. Two reviewers (SEH, KN) appraised independently the methodological quality of all studies. Cohen's kappa was 0.855 (p < 0.001), suggesting "strong" inter-rater agreement. ICC was 0.92 (95% CI 0.91-0.94, p < 0.001), indicating excellent inter-rater reliability.

Thematic synthesis
The descriptive themes of this meta-synthesis highlight the overt ideas in the data and therefore are descriptive rather than interpretative in their nature. The six descriptive themes relate broadly to: 1) listening abilities (or behaviours) which are perceivable by adults with HL when listening in the communication situations of daily life; 2) external elements which influence listening capability, ability and behaviour; 3) the wider psychosocial impacts of HL attributed by participants to listening; 4) perspectives, roles, and implications of communication partners on the listening abilities of adults with HL; 5) the role of self-efficacy; and 6) cognitive load. The themes include data extracted to 212 codes from all the included studies (n = 46). A brief description of each theme is presented below. Table 3 presents exemplar extracts and coding of the original studies for each descriptive theme.
Descriptive theme 1: Perceived listening ability as navigation (within the dynamic, transactional landscape of communication). Data from 43 (93.5%) studies contributed to this theme which describes self-reported listening ability from the perspective of adults with HL. These data suggested listening is perceived by adults with HL as a navigational act, a series  of negotiations, both with oneself and with others. Describing listening as navigation emphasises the concepts of motion and energy, an acknowledgment of the transactional and fluid nature of communication. The actions of an individual reflect a dynamic, choice-making exercise that individuals engage as they steer a course through a communicative interaction. Listening acts were described in different ways by the body of studies. Data from 29 studies suggested that listening ability or behaviour could be classified as adaptive or maladaptive, meaning it either facilitated or impeded interaction [22,39,[41][42][43][44][45][46][47][48][49][50][51][52]54,[56][57][58][59][60][61][62][63][64][65][66][67][68][69][70]. In 12 studies  [50] (Continued )  [47]. Descriptive theme 2: External modifiers of perceived listening ability. Data from 39 (84.8%) studies showed that perceived listening ability was often defined by adults with HL in terms of success/failure. This binary characterisation of listening lacked nuance, yet these data showed that adults with HL had a finely tuned awareness of the gradations of their ability. Participants were suggested to undertake differentiation or qualification of their perceived ability based on a range of external modifiers [44,48,57,58,64,78]. Participants described environmental modifiers of their perceived listening ability including the presence/absence of background noise, physical characteristics of the environment such as room size, reverberation, and lighting [46,57,64]. Ten studies described a participant's location relative to the sound source (i.e., distance to speaker) as influencing adults' with HL perceived listening ability. Speaker characteristics were also used by adults with HL to differentiate their listening abilities. Listening to a single speaker was perceived to be easier than listening to multiple speakers [47][48][49]60,70,77,78]. Female speakers, children and specific vocal characteristics of the speaker (e.g., soft speech, pitch, rate of speech, familiarity) were described by adults with HL as determiners of their perceived ability to listen [43,60,78]. Data from 16 studies suggested that technical supports such as hearing devices (i.e., hearing aids, FM systems and cochlear implants), smart phone technology, and captioning were also considered by adults with HL to be modifying influences [41,42,44,46,[49][50][51][56][57][58]64,69,70,73,75,80]. Lastly, information complexity was identified by participants to be a determiner of their ability to listen [57,64]. Altogether,  [43,46] and stress (8 studies) [42,43,51,59,64,72,80,83], as well as rejection/exclusion from social groups (6 studies) [41,43,44,46,54,56]. Participant experiences of stigma relating to HL were reported in 12 studies [39,[42][43][44][45]54,57,58,61,65,82,83]. Eight studies suggested that acceptance of hearing difficulties and an ability to adapt and accommodate HL both within one's self-identity and, more practically, within their communicative interactions, was a determiner of an individual's psychosocial state [39,49,53,54,61,65,68,70]. Individuals who expressed a willingness to accept and accommodate their HL were suggested to have a more positive outlook, higher self-efficacy, increased participation and independence, and were agile with skill deployment to facilitate listening success within their communicative interactions.
Descriptive theme 6: Cognitive load. Data from 18 (39.1%) studies described listening for communication by adults' with HL as requiring additional investment of cognitive energy not required by individuals who do not have HL [40,[43][44][45][46]48,50,[56][57][58]60,64,66,71,72,78,82,85]. This energy requirement was described as listening effort in the included studies and was considered to result in listening-related fatigue. Three studies [41,57,58] described cognitive load as an increased requirement for attention and concentration when listening which participants suggested was something that happened without conscious awareness but was influenced by an individual's motivation to listen [57,58]. Five studies described attention and concentration in terms of participants' ability to successfully divide their attention between listening and a concurrent task [45,57,58,64,82]. Four studies suggested that the increased cognitive load required for listening was experienced and understood by participants in the context of the dynamics of communication [40,43,57,78]. In these studies, participants suggested that the increased need for cognitive processing when listening was experienced by participants as a time lag and difficulty keeping pace and getting a turn within in a conversational exchange. Ten studies suggested the increased processing demands experienced by adults with HL led to downstream mental and physical fatigue and cognitive resource depletion [40,46,48,50,[56][57][58]60,64,72].
Analytic themes: Liminality and reciprocity. The six descriptive themes were suggested to be related by the two analytic themes of liminality and reciprocity. Fig 2 presents a hypothetical model of relationships between the descriptive themes based on the review findings. Firstly, we propose that adults with HL have insight into a range of listening-related skills providing these are supraliminal (i.e., above the threshold of conscious perception). The data

PLOS ONE
suggested that adults with HL rely on external factors, as perceivable, supraliminal features, to grade their listening abilities against task difficulty. Within the context of listening for communication, adaptive or compensatory skills (e.g., communication techniques and behaviour modifications) that enable adults with HL to experience listening success were suggested to be a component of perceived listening ability. Secondly, we propose reciprocal relationships between the descriptive themes. For instance, adults' with HL perception of their listening abilities was informed by listening self-efficacy (i.e., perceived capability for listening). In turn, participants' performance (listening ability) in everyday communication situations was suggested to reinforce listening self-efficacy. Data from the contributing studies suggested that low listening self-efficacy had negative impacts on future listening-related performance, including skill selection and utilisation (i.e., selection of maladaptive v. adaptive listeningrelated behaviours). Social and psychological constructs were suggested to influence selfreported listening abilities and self-efficacy. In a reciprocal fashion, both were suggested to influence adults' with HL psychosocial status. Lastly, data suggested that participants considered listening effort and downstream fatigue effects to be influencers of their listening abilities and performance in real-world communication. In turn, skill selection and deployment were suggested by participants to contribute to the extent of their listening-related fatigue.

Confidence in the review findings
An overall assessment of confidence in each descriptive theme was conducted by applying the GRADE CERQual approach. Confidence ratings ranged from "low" to "moderate". Themes D1-4,6 were appraised as "moderate confidence" and Theme D5 (Self-efficacy for listening) was appraised as "low confidence". A rating of "moderate confidence" suggested that a review finding was likely a reasonable representation of the phenomenon of interest and a rating of "low confidence" meant the review finding is likely an incomplete representation. Individual domain ratings and the confidence rating for each theme are summarised in Table 4. S2 Table  presents results of the full GRADE CERQual evaluation.

Discussion
This systematic review is the first qualitative meta-synthesis to examine perceived listening in HL from a metacognitive perspective. Through a review of primary qualitative studies, we explored adults' with HL and their communication partners conceptualisation of their listening abilities. Six descriptive themes were identified from the findings of 46 included studies. These themes described: listening abilities and component skills from the lived experience perspective, listening self-efficacy, the perceived requirement for additional cognitive resource allocation when listening, and the psychosocial impacts of listening with HL. A sixth theme capturing the implication of HL on communication partners provided an extended perspective on adults' with HL listening abilities in the context of interactive communication. Descriptive themes were linked through the higher-order analytic themes of liminality and reciprocity. CERQual grading of the descriptive themes were "low" (Theme D5-Self-efficacy for listening) and "moderate" confidence (Themes D1-4, D6), suggesting most themes were likely to be a reasonable representation of the available evidence.
Metacognition may be defined as "knowledge [emphasis added] of one's knowledge, processes, and cognitive and affective states; and the ability to consciously and deliberately monitor and regulate [emphasis added] one's knowledge, processes and cognitive and affect states." [14] (p.4) and reflects the analytic theme of liminality identified in this review. Themes D1, D2, D4, D5 and D6 suggest that adults' with HL and have knowledge of component skills and listening behaviours that they and their communication partners are required to adopt for effective communication. Data from the contributing studies also suggested that adults with HL and their communication partners engage in monitoring and regulation through the deliberate adaptation of listening behaviours considered to increase the likelihood of communicative success. Similar findings have been reported in the second language learning literature. A qualitative study explored deployment of listening strategies (i.e., interest management, asking pre-questions, and elaboration strategies) by L2 learners and found that participants consistently reported more comprehensive understanding, deeper level of processing, and improved processing characteristics (e.g., sustaining attention and selective focus, better retention) when metacognitive strategies were appropriately aligned to the listening situation [86]. However, metacognition is known to be sensitive to listener characteristics. In a review exploring the contribution of cognition to speech-in-noise listening, listening strategy selection was found to depend upon listener characteristics such as age, hearing status, linguistic competency, educational attainment, and cognitive status [87]. Metacognitive judgements (i.e., monitoring which the authors define as one's awareness of cognitive processing) have been found to be largely preserved in older adults relative to younger adults but only to the extent that monitoring does not draw upon executive attention [88]. Further work is needed, building upon this body of work and the findings of this meta-synthesis, to understand the differential contribution of various listener characteristics on metacognitive knowledge, monitoring, and regulation in the context of HL. ii Fit between original study aims, context and the review aims and context. iii Fit between original study findings and review themes. iv The extent to which themes are supported by quantitative evidence (number of studies and nodes supporting theme) and qualitative. evidence (richness of data supporting a theme). v Overall rating based on judgements for the four domains and scored as: High, moderate, low, or very low [34]. https://doi.org/10.1371/journal.pone.0276265.t004 Theme 3 (psychosocial impacts) suggested that adults with HL have a rich, nuanced knowledge of their emotional states in the context of HL. This finding is unsurprising given the established literature on the social and psychological consequences of HL. For example, hearing is a recognised risk factor for loneliness and social isolation, lower generic quality of life, and is associated with increased odds of psychological distress and utilisation of health services [89][90][91]. The significant psychosocial impacts reported by adults with HL across the included studies may be considered a reflection of their metacognitive beliefs. Metacognition may also account for the finding that self-efficacy (Theme 5) appeared to influence strategy deployment and coping. Self-Regulatory Executive Function (S-REF) theory proposes that metacognitive factors (e.g., beliefs about cognition, emotion and behaviour) can provoke and maintain states of psychological distress and predispose individuals towards maladaptive coping strategies (e.g., heightened self-focussed attention, threat monitoring, avoidance) which further compromise their psychological wellbeing [92]. Negative metacognitive beliefs have been associated with perceived stress and negative emotion in healthy volunteers and have been related to anxiety, depression and quality of life in patients with chronic conditions and their caregivers [93,94]. Although not explicitly stated, Barker et al., in a systematic review and qualitative meta-synthesis exploring the psychosocial experiences of people with HL and the communication partners, allude to the influence of metacognition, proposing that perceptions of self may influence the effect of HL and subsequent coping [95].
The influence of social factors on metacognition in individuals is well established in the literature. Frith (2012) reasons that explicit metacognition, which enables individuals to reflect on and justify their behaviour, is determined largely through social interactions with others and is a means by which individuals overcome the lack of direct access to underlying cognitive processes, including those recruited when listening [96]. Theme 4, which presented communication as a dynamic, reciprocal process with communication partners playing a key role in ensuring communicative success for the person with HL, underscores Frith's proposition that explicit metacognition is, in part, socially constructed. Recent work from Harris et al. (2019) applies this understanding to investigate memory collaboration in elderly couples. Findings from this study demonstrate that couples used established, sensitive and dynamic communication strategies to enhance recall [97]. A review by Cooke et al. also describes overt modifications to speech directed at listeners with HL aimed at promoting audibility, increasing coherence, enhancing linguistic information or decreasing cognitive effort associated with the listening task [98]. The present trend to include interlocutors or observers to enhance the ecological validity of hearing research suggests there is a growing awareness by cognitive hearing scientists of communication partners' influence on adults with HL self-appraisal and consequently their self-management of real-world listening (for examples, see [99][100][101]). Understanding the communication mechanisms in interpersonal relationships will be key if measurement of communication ability is to be both valid and reliable.

Strengths and limitations
This study has some limitations. The GRADE CERQual approach, despite providing a systematic process for appraising quality of the findings, did not provide sufficiently operationalised acceptability criteria to support reviewer judgments, with an associated risk of bias. To address this limitation, a second member of the review team (KN) reviewed all GRADE CERQual ratings with the involvement of a third reviewer (IB) to reach consensus when discrepancies were identified. Ideally, two reviewers would independently undertake a GRADE CERQual assessment of evidence quality; however, this was not possible in the current study due to resource limitations. High kappa and ICC values for the CASP assessment of articles' methodological quality provides supporting evidence of strong inter-rater agreement and reliability between the two reviewers.
Second, limiting searches to studies published in English-language journals raises the possibility of publication bias. Only one article published in a language other than English was identified through the electronic database searches which suggests relevant articles were likely to have been published in English and therefore identified by the searches. Third, this review presents a secondary analysis of primary data; therefore, any methodological limitations of the included studies were carried forward to this review. For example, the relationship between researcher and participants was not reported adequately for most of the included studies. Inadequate accounts of reflexivity raised uncertainty about the handling of researcher bias and downgrading of a study's methodological quality. GRADE CERQual assessment of the review findings enabled these methodological limitations of the primary studies to be considered in the context of the quality of the overall findings of this review. Last, it was not possible to undertake sub-analyses to explore age-related difference as data in the primary studies did not explicitly differentiate between younger v older listeners. In addition, few articles included participants with mild or moderate hearing loss (MMHL); therefore, it was not possible to mine the experiences of listening for this group. Lack of representation across the full range of hearing loss has implications for conceptual operationalisation of a PRO and for ensuring complete construct coverage, particularly at the extreme of the measurement continuum (i.e., perceived listening ability at mild or profound levels of hearing loss).

Implications for research and practice and directions for future research
This review, as a secondary analysis of primary data, provided a synthesis of current research exploring metacognition of listening from a lived experience perspective of hearing loss. Studies are now required to validate the proposed themes in primary qualitative studies. The review findings contribute an alternative perspective to the body of literature on perceived listening ability and metacognition which has drawn extensively from studies of second language learners in an educational context. Further work to explore perceived listening ability across subgroups of the population adults with HL (e.g., single-sided deafness, older v younger adults) is now needed to ensure conceptual representativeness and construct coverage. Further work is also needed to investigate mediating role of listener characteristics on metacognitive knowledge, processes and behaviour when a hearing loss is present. Findings from this review will be used to inform the content and design of a new patient reported outcome measure (PROM) of perceived listening ability in hearing loss. Findings may also be used to inform trial design by ensuring patient-reported outcome (PRO) selection that is representative of the knowledge, processes and experiences of listening considered important to adults with HL.
Conceptualisation of perceived listening ability in a metacognitive framework could inform the development of supportive interventions designed to mitigate the wider impacts of HL. The findings could also inform the design of trials to investigate the efficacy and effectiveness of for aural rehabilitation (AR) interventions. As a heuristic framework, metacognition is relevant because the underlying mechanisms of AR are not yet well developed and high-quality evidence of AR benefit is limited [102]. Support for the implementation of a metacognitive framework in AR may be drawn from the wider metacognition literature. Goal-based metacognitive strategy interventions have been shown to improve attention, executive functioning, self-awareness, and social communication in adults with traumatic brain injury (TBI) [103][104][105]. Second language (L2) learners receiving explicit communication strategy instruction have been found to have greater metacognitive awareness, defined as conscious awareness of communication strategies, and increased frequency of use of "high-quality" communication strategies compared with controls [106]. In the AR setting, a metacognitive framework that conceptualises the components of functional listening could guide the identification and targeting of specific skills, behaviours, knowledge and processes for inclusion in a self-management intervention. Awareness of the contribution of cognitive and affective states to perceived listening ability could support counselling and information giving in the context of clinical audiology practices. A metacognitive understanding of relationships between hearing loss and its social, psychological and emotion impacts could provide opportunities for intervention through metacognitive modification and training.

Conclusions
This meta-synthesis of qualitative studies explored perceived listening ability and hearing loss from a metacognitive perspective. By considering individuals' knowledge and understanding of their own listening abilities and their capacity to monitor and regulate their listening behaviour, the findings underscore the dynamic communication complex in which real-world listening is situated. As a heuristic, the findings provide a more holistic framing of listening function with potential to inform the design of empirical studies with greater ecological validity, concept elicitation for new patient-reported outcome measures, and the development of supportive interventions, that enable individuals living with hearing loss to more effectively manage the dynamic and unpredictable communication demands of daily life.
Supporting information S1 Checklist. PRISMA Checklist. Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist. (DOCX) S1